Studien

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Mai

An fMRI Study of Neuronal Specificity in Acupuncture: The Multiacupoint Siguan and Its Sham Point

IntroductionAcupuncture is a traditional Chinese medicine (TCM) that has been used for thousands of years with empirical evidence of effectiveness. Recently, clarifying the intrinsic mechanisms of its clinical effects has become increasingly popular research. According to the traditiona ltheory of acupuncture, stimulation at specific acupoints will produce effective bodily responses that can be used to treat certain diseases. Much research has been devoted to demonstrating the mechanisms underlying acupoint specificity. Since the1990s, development in noninvasive brain imaging techniques such as positron emission tomography and functional magnetic resonance imaging (fMRI) has accelerated the progress of connecting the effects of acupuncture with the central nervous system [1, 2]. Findings have revealed relationships between therapeutic acupuncture and brainactivity in areas such as visual cortex [3, 4], language regions [5], limbic system, pain regions [1, 6–10], and somatosensory cortex [11]. While these results have shed some light on the issue of neuronal acupuncture specificity, defining an appropriate control when evaluating specificity is still controversial [12– 16]. A sham point design that entails needling at the same depth and with the same pattern but at a non acupoint located 10 millimeters away from the real one. However, Cho et al. Reported that acupuncture ise ffective regardless of the choice of point at least for pain and analgesic response, which directly questioned the existence of point specificity [17]. Some studies also support the statement that differences between effects produced by sham and real acupuncture have remained unclear[18,19]. The Siguan acupoint is a combination of bilateral LI4 (Hegu) and Liv3 (Taichong). In TCM, multiacupoint acupuncture is widely used to enhance the therapeutic effects as well as to avoid side effects. Siguan has been conventionally used for several symptoms, especially those of gastrointestinal and neurological disorders [20,21]. Here, we chose to evaluate the multiacupoint specificity of Siguan usingfMRI,which has rarely been reported. Based on results from studies using a single acupoint, we hypothesized that Siguan acupuncture may activate mores pecificbrain regions than ist sham point.We also expected to find both differences and commonalities betweenresponses elicited by Siguan and its single acupoint components (Liv3/LI4). Thus, this study aimed to demonstrate whether multiacupoint acupuncture elicits specific activity in the human brain.

3. Results

3.1. Results of Acupuncture Stimulation at the Siguan Acupoint.Compared with the resting-state, acupuncture at the real acupoints activated brain regions primarily in the left calcarinegyrus, bilateral middleo ccipital gyrus(BA19),bilateral middle temporal gyrus (left BA 22), left inferior temporal gyrus, left inferior frontal gyrus, left superior medial prefrontal gyrus (left BA 10), right anterior cingulate cortex (rightBA10),left post central gyrus, left caudate nucleus, and the bilateral cerebellum(Crus2andVIII). This result is based on the anatomical location of the peakvoxel in the activated cluster. When taking whole clusters into consideration, we also found higher activity in the right superior medial prefrontal gyrus(rightBA10),right calcarine gyrus, and the bilateral precuneus. The details of these regions are presented inTable1 andFigure2.

3.2. ResultsofAcupunctureStimulationattheShamAcupoint.Compared with the resting-state, acupuncture at the sham acupoints activated brain regions primarily in the left anterior and middle cingulate cortices, right caudate nucleus, right insula, left angular gyrus, and right cerebellum(VIII).Considering the entire clusters, increased activity was also seen in right anterior and middle cingulate cortices.

3.3. Comparison between Real and Sham Acupuncture.
Brain regions that were activated more by real acupuncture stimulation than by sham point acupuncture were mostly located in the left inferior frontal gyrus, right superior medial prefrontal gyrus (right BA 10), left mid-orbital gyrus, right medial temporal pole (right BA 38), left parahippocampal gyrus, left precuneus (left BA 23), left fusiform gyrus (left BA 20), left pallidum, and left middle occipital gyrus. When taking whole voxels into account, increased signal was also present in the right precuneus(rightBA23), right fusiform gyrus, left putamen, right mid-orbital gyrus, bilateral rectal gyrus (BA 11), and the left inferior temporal gyrus.

5. ConclusionHere, we focused on confirming the specificity of multi acupoint acupuncture using Siguan and a sham acupoint design. Extensive bilateral cortical and subcortical structures showed specific activation during Siguan stimulation while sham point only activated brain regions that are not thought to be related to specific needling location. Our findings suggest Siguan may elicit more specific and extensive activities in human brain than ist sham point.

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